Chlorine quality monitoring system and method

ABSTRACT

An apparatus and method for monitoring the product quality of chlorine in which a sample stream of chlorine is taken from a chlorine stream and a portion of the sample stream is passed to one of three different analyzers for detection of various contaminants. A common data acquisition network receives data from each analyzer for integration and output. The analyzers include a bromine in chlorine analyzer, a non-condensable gas in chlorine analyzer, and a halocarbon in chlorine analyzer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the monitoring of the productquality of chlorine. More particularly, this invention relates to asystem and method for monitoring chlorine for the presence of variouscontaminants.

2. Background

The demand for purer chlorine products is generally increasing.Industrial chlorine users need to produce higher quality productsderived from chlorine in order to meet increasingly stringent safety andenvironmental standards, as well as to improve manufacturing operations.For example, contaminants in chlorine such as non-condensable gasesincluding oxygen, nitrogen and carbon dioxide are undesirable becausethey generate unwanted chemical waste which is costly to dispose of.These contaminants, which may remain in the excess chlorine from achemical process, tend to deplete the scrubber through which the excesschlorine is passed for disposal, as well as form other compounds whichmust be disposed of. Bromine in chlorine contaminates the products madefrom chlorine, and decreases the reactivity of intermediates made fromchlorine, thereby effecting the manufacture of the final product.

Additionally, public chlorine users such as municipalities need purerchlorine for water treatment to reduce the costs involved in the removalof carcinogenic materials such as halomethanes. Potable waters, whichare normally disinfected with chlorine, must meet imposed standards oncontaminants such as chloroform and carbon tetrachloride.

Due to the demand for purer chlorine by its users, chlorine manufacturesare being increasingly compelled to monitor the various contaminants inchlorine during the manufacturing process to ensure that the chlorinebeing produced meets the demand for purity and to be able to take rapidcorrective measures to reduce and/or eliminate the contaminants whenthey begin to appear. Particular contaminants which may be present inthe produced chlorine and which are desired to be eliminated, or atleast greatly reduced, include bromine, non-condensable gases such asoxygen, nitrogen and carbon dioxide, and halocarbons, includingmethylene chloride, chloroform and carbon tetrachloride. In order tomonitor the contaminants and have the ability to take corrective action,it is necessary that a suitable system and method be available whichwill accurately detect and measure such contaminants and which can beused on-line at the production site and take samples directly from theprocess stream.

SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention toprovide an improved system and method for measuring contaminants inchlorine.

A more specific object of the present invention is the provision of asystem and method for measuring contaminants in chlorine which is easyto use and which can measure a plurality of different contaminants.

Yet another object of the present invention is the provision of a systemand method for measuring contaminants in chlorine which can be used online.

Still another object of the present invention is the provision of asystem and method for monitoring contaminants in chlorine which can beused continuously.

A further object of the present invention is the provision of a methodand analyzer which will detect and measure the presence of bromine inchlorine.

Yet still a further object of the present invention is the provision ofa method and analyzer which will detect and measure the presence ofnon-condensable gases in chlorine.

Yet still another object of the present invention is the provision of amethod and analyzer which will detect and measure the presence ofhalocarbons in chlorine.

These and other objects and advantages of the present invention may beachieved through the provision of a method for monitoring the productquality of chlorine which comprises taking a sample stream of chlorinefrom a stream of chlorine, passing a different portion of said samplestream to each of a plurality of analyzers, detecting the presence ofbromine in the sample stream of chlorine by a first one of saidanalyzers, detecting the presence of non-condensable gases in the samplestream of chlorine by a second one of said analyzers, detecting thepresence of halocarbons in the sample stream of chlorine by a third oneof said analyzers, and passing the data regarding the presence of thedetected material by each of the analyzers to a common data acquisitionnetwork for integration and output of the data.

An apparatus for monitoring the product quality of chlorine inaccordance with the present invention may comprise a line for taking asample stream of chlorine from a chlorine stream and a plurality ofanalyzers. Lines may be provided for taking a plurality of portions ofthe sample stream and passing a different portion of said sample streamto each of said analyzers, the first of said analyzers being a brominein chlorine analyzer, a second of said analyzers being a non-condensablegas in chlorine analyzer, and a third of said analyzers being ahalocarbon in chlorine analyzer. A data acquisition network common toall of the analyzers may be provided for receiving data from eachanalyzer and integrating and outputting the data.

According to another feature of the invention, a method of detecting thepresence of bromine in a sample of chlorine may comprise reacting astream of the chlorine sample with a reagent to form bromide ions,chloride ions and gas in an aqueous mixture, separating the gas from theaqueous mixture containing the bromide ions and chloride ions, injectinga sample of the aqueous mixture containing the bromide ions and chlorideions into a liquid carrier stream, separating said bromide ions and saidchloride ions in said carrier stream, and passing said carrier streamwith said separated ions through an ultraviolet detector and detectingthe presence of the bromide ions in the sample passing therethrough.

An analyzer for detecting the presence of bromine in a sample ofchlorine in accordance with the present invention may comprising areaction zone for reacting a stream of the chlorine sample with areagent to form bromide ions, chloride ions and gas in an aqueousmixture, a separator for separating the gas from the aqueous mixturecontaining the bromide ions and chloride ions, a liquid carrier stream,an injector for injecting a sample of the aqueous mixture containing thebromide ions and chloride ions into said liquid carrier stream, achromatographic column for separating said bromide ions and saidchloride ions in said carrier stream, and an ultraviolet detector fordetecting the presence of the bromide ions when the carrier streamcontaining the separated bromide and chloride ions is passedtherethrough.

A method of detecting the presence of non-condensable gases in a sampleof chlorine according to the present invention may comprise injecting asample of chlorine into a gaseous carrier stream, passing said carrierstream with said sample into a first chromatographic column to separateany non-condensable gases in said sample from the chlorine, passing saidcarrier stream with the non-condensable gases to a secondchromatographic column while said chlorine remains in said first column,separating a first set of non-condensable gases from at least one othernon-condensable gas in said second chromatographic column, temporarilystoring said first set of gases in a third chromatographic column whilesaid another non-condensable gas is passed to a detector for detectionand measurement of that particular gas, passing said first set ofnon-condensable gases after separation to said detector upon completionof the passing of said another non-condensable gas, and backflushingsaid chlorine from said first chromatographic column with a stream ofcarrier gas to remove the chlorine from the column and out of thesystem.

Further, in accordance with the present invention, an analyzer fordetecting the presence of non-condensable gases in a sample of chlorinemay comprise an injector for injecting a sample of chlorine into agaseous carrier stream, a first chromatographic column to separate anynon-condensable gases in said sample from the chlorine, a secondchromatographic column for separating a first set of non-condensablegases from at least one other non-condensable gas, a storage column fortemporarily storing and separating said first set of gases from eachother, a detector for detecting the presence of the non-condensablegases passing therethrough, a valve arrangement for passing said anothernon-condensable gas to said detector while said first set remains insaid storage column and for passing said first set of non-condensablegases to said detector upon completion of the passing of said anothernon-condensable gas and while said chlorine remains in said firstchromatographic column, and means for backflushing said chlorine fromsaid first chromatographic column with a stream of carrier gas to removethe chlorine from the column and out of the system.

A method of detecting the presence of halocarbons in a sample ofchlorine according to the present invention may comprise injecting asample of chlorine into a first carrier stream, passing said firststream containing said sample through a chromatographic column toseparate any halocarbons from each other and from the chlorine,diverting the chlorine from the system after it exits the column,passing a first group of halocarbons exiting from the column to a flameionization detector for detection of each component of said first group,and passing a second carrier stream through said chromatographic columnafter said first group of halocarbons have exited therefrom in adirection opposite to the flow of the said first stream to carry anyhalocarbons remaining in the column from the column to the detector formeasurement as a group.

An analyzer for detecting the presence of halocarbons in a sample ofchlorine according to the present invention may comprise an injector forinjecting a sample of chlorine into a first carrier stream, achromatographic column to separate various halocarbons from each otherand from the chlorine, a flame ionization detector for detection of saidhalocarbons, a diverter for diverting the chlorine after it exits saidcolumn away from the detector, and a valve arrangement for directing afirst stream of carrier fluid to carry a first group of separatedhalocarbons from said chromatographic column to said detector and fordirecting a second carrier stream through said chromatographic column ina backward direction after said first group of halocarbons have exitedtherefrom and carry any halocarbons remaining in the column from thecolumn to the detector for measurement as a group.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the present invention will become moreapparent by reference to the following detailed description and to theaccompanying drawings in which:

FIG. 1 is a schematic drawing of the overall monitoring system of thepresent invention;

FIG. 2 is a schematic diagram of the portion of the system of FIG. 1comprising the analyzer for the detection and measurement of bromine inchlorine;

FIG. 2a is view similar to FIG. 2, but showing a modified analyzer fordetecting and measuring bromine in chlorine;

FIG. 3 is a schematic diagram of the control valve shown in FIG. 2, withthe valve schematically shown in its injecting position;

FIG. 4 is a schematic diagram of the portion of the system of FIG. 1comprising the analyzer for the detection and measurement ofnon-condensable gases in chlorine, and showing the position of thevalves and flow through the system while the system is inactive;

FIG. 4a is view similar to FIG. 4, but showing a modified analyzer fordetecting and measuring non-condensable gases in chlorine:

FIG. 5 is a schematic diagram of the analyzer shown in FIG. 4 showingthe positions of the valves and flow through the system during one stageof the sampling cycle;

FIG. 6 is a schematic diagram of the analyzer shown in FIG. 4 showingthe positions of the valves and flow through the system during anotherstage of the sampling cycle;

FIG. 7 is a schematic diagram of the analyzer shown in FIG. 4 showingthe positions of the valves and flow through the system during a furtherstage of the sampling cycle;

FIG. 8 is a schematic diagram of the analyzer shown in FIG. 4 showingthe positions of the valves and flow through the system during thelatter stage of the sampling cycle;

FIG. 9 is a schematic diagram of the portion of the system of FIG. 1comprising the analyzer for the detection and measurement of halocarbonsin chlorine, and showing the position of the valves and flow through thesystem while the system is inactive;

FIG. 9a is view similar to FIG. 9, but showing a modified analyzer fordetecting and measuring halocarbons in chlorine:

FIG. 10 is a schematic diagram of the analyzer shown in FIG. 9 showingthe positions of the valves and flow through the system during one stageof the sampling cycle; and

FIG. 11 is a schematic diagram of the analyzer shown in FIG. 9 showingthe positions of the valves and flow through the system during anotherstage of the sampling cycle.

DETAILED DESCRIPTION

Referring to the drawings, and particularly FIG. 1, there is shown aschematic diagram of a system 10 for monitoring the quality of chlorinewhich incorporates the principals of the present invention. In general,the preferred system comprises a vaporizer 12 to convert the incomingliquid chlorine into gaseous chlorine, a bromine in chlorine analyzer14, a non-condensable gas in chlorine analyzer 16, a halocarbons inchlorine analyzer 18, and a data acquisition network 20. The dataacquisition network 20 may include a computer 22, a monitor 24, akeyboard 26 and an output device such as a printer 28.

More specifically, a chlorine sample input line 30 is connected to aline 32 of the process stream containing the chlorine. The connection ofthe input line 30 to the process stream line 32 is preferable made at apoint downstream of the process compressor which converts the chlorineinto its liquid form. Accordingly, the sample of the chlorine taken fromthe process stream line 32 is preferably in liquid form. By taking thesample after the process compressor and in the liquid state, it isensured that the sample will contain all the contaminants as in thechlorine product. Such process stream line 32 may be a feed line to achlorine storage vessel or to a transport vessel such as a rail tank caror the like.

The input line 30 contains a cut-off valve 34 adjacent the connection tothe process stream line 32. This valve 34 may be any suitable type ofshut off valve such as a needle valve. A pressure regulator 36 isprovided in the input line 30, downstream of the shutoff valve 34 toregulate the pressure of the incoming liquid chlorine. A pressure gauge38 is provided in the input line 30, down stream of the pressureregulator 36 to provide an indication of the pressure of the incomingchlorine.

The input line 30 is connected at its downstream end to the vaporizer 12which serves to change the liquid chlorine into gaseous chlorine. Thevaporizer 12 may be a heat exchanger 40 which is heated by electricalpower such as electrical heating coils 42 or may utilize steam as theheat source. The heat exchanger 40 should be maintained at a temperaturesufficient to ensure that the chlorine exiting therefrom is in itsgaseous form and there is complete vaporization and not fractionation ofthe volatiles. By way of example, the heat exchanger 40 may bemaintained at a temperature between 100° C. and 50° C.

The chlorine sample stream exits the vaporizer 12 in gaseous form into agaseous chlorine line 44 which splits into three input lines, a bromineanalyzer input line 46, a halocarbon analyzer input line 48 and anon-condensable gas analyzer input line 50. Each of the input lines 46,48 and 50 have a shut-off valve 52 positioned therein to shut off theflow of gaseous chlorine to its respective analyzer when necessary, as,for example, in the event that maintenance of an individual analyzer isneeded. Such valves 52 may be any suitable type of shut-off valveresistant to chlorine and which can be manually actuated to shut off theflow. The valves 52 may preferable be needle valves.

Excess chlorine from each of the analyzers is discharged through asample return line 54 back into a process stream line 56. As thechlorine being returned is in gaseous form, the excess chlorine shouldbe returned to the process stream at a point at which the chlorinetherein is also is gaseous form. Flow meters 58 are positioned in thereturn conduit 54, one associated with each of the analyzers 14, 16 and18 to provide an indication of the flow of the excess chlorine from itsrespective analyzer. A shut-off valve 60 is positioned in the returnconduit 54 immediately before its connection to the process stream line56 to provide for isolation of the system 10 from the process streamwhen necessary.

The data acquisition network 20 receives input from the individualcontrollers of each of the analyzers 14, 16 and 18, and converts theinput into suitable data for recording and output.

FIG. 2 shows a schematic diagram of the bromine in chlorine analyzer 14.The analyzer 14 includes generally a source 64 of an aqueous solution ofhydrazine which is caused to react with the chlorine sample in areaction area 66 to form chloride ions, bromide ions from any brominepresent in the sample and nitrogen gas. The reacted gas-liquid mixtureflows to a separator 68 in which the nitrogen escapes through a vent 70while a portion of the liquid is discarded into a waste receptacle 72. Apump 74 meters a portion of the remaining liquid to a sampling valve 76.The sampling valve 76 serves to cyclically connect the liquid from thepump 74 to a sample loop 78. A carrier fluid from a source 80 isconnected for flow to the sampling valve 76. The sampling valve 76cyclically connects the carrier fluid with the sample loop 78 forcarrying the sample from the sample loop 78 through a chromatographiccolumn 82 and then to an ultraviolet detector 84. A microprocessor 85converts the signals from the detector 84 into an output indicative ofthe amount of bromine present in the sample.

More specifically, still referring to FIG. 2, the bromine in chlorineanalyzer 14 receives the gaseous chlorine from the vaporizer 12 throughline 46. A portion the chlorine from line 46 is passed to the reactionarea 66 by means of a conduit 86. The excess chlorine exits the brominein chlorine analyzer 14 through the sample return line 54 and isreturned to the chlorine process stream. A flow control valve 88 isprovided in the conduit 86 to control the flow of the chlorine into thereaction area 66. A flow meter 89 is also positioned in the conduit 86to provide an indication of the flow rate of the chlorine to thereaction area 66.

The source 64 of the aqueous solution of hydrazine may be in a suitablestorage vessel such as a tank 90 which contains a supply of a hydrazineaqueous solution (N₂ H₄) to provide a source of hydrazine to react withthe chlorine. A conduit 92 connects the contents of the storage vessel90 with a pump 94 which serves to meter a small flow of the hydrazinesolution into a line 96 which connects with the conduit 86 containingthe chlorine sample at a junction 98 located upstream of the flow meter89. When the hydrazine enters the conduit 86, it begins to immediatelyreact with the chlorine to form chloride ions, bromide ions from anypossible bromine present in the chlorine sample, and nitrogen gasaccording to the formula: ##STR1##

This reaction continues to progress in the conduit 86 and into a reactor100. The reactor 100 my be simply a coiled tubing of a length sufficientto ensure that the reaction is completed before the liquid- gas mixtureleaves the reactor 100 and enters the separator 68. A reaction outputline 102 connects an outlet 104 of the reactor 100 with an inlet 106 inthe bottom 108 of the separator 68 to provide for the passage of thereacted gas-liquid mixture to the separator 68. The separator 68 may beany suitable type of closed vessel with the vent 70 preferable in itstop surface 110 and an overflow outlet 112 in its side wall 114 at anappropriate height from the bottom 108 of the separator 68. The overflowoutlet 112 is connected to a waste line 116 having a U-shaped trap 118and a vent 120 therein. The waste line 116 is connected to the wastereceptacle 72 which serves to collect the discarded liquid from theseparator 68. The trap 118 in the waste line 116 serves to prevent anygas from passing from the separator 68 to the waste receptacle 72.

The separator 68 thus serves to permit the nitrogen gas to escapethrough the vent 70 while a portion of the liquid is discarded to thewaste receptacle 72. A portion of the remaining liquid passes through asample outlet 122 in the bottom 108 of the separator 68 to which one endof a sample feed conduit 124 is connected. The other end of the samplefeed conduit 124 is connected to the metering pump 74. A sample infeedconduit 126 connects the outlet of the pump to the sampling valve 76.

The sampling valve 76 serves to connect the flow of the reacted liquidmixture from the metering pump 74 cyclically to either the sample loop78 or directly to a waste line 128 leading to a waste receptacle 130.Additionally, the sampling valve 76 serves to connect the source 80 ofthe carrier fluid cyclically to either the sample loop 78 for carrying asample in the loop 78 to the chromatographic column 82, or to a line 132going directly to the chromatographic column 82.

A carrier fluid supply line 134 is provided to connect the source 80 ofa carrier fluid to an inlet 136 of a metering pump 138. A carrier fluidfeed line 140 has one end connected to an outlet 142 of the meteringpump 138 and its other end connected to the sampling valve 76.

The carrier fluid is preferably an aqueous solution of sodium chloride,but other salts such as potassium chloride may be used.

The sampling valve 76 is preferably a standard six port sample injectionvalve. Valves of this type may generally include a stator 144 having sixports 146, 148, 150, 152, 154 and 156 therein as indicated by the smallcircles shown in FIG. 2. The two heavy arcs 158 and 160, as shown in thedrawing, represent the connecting passages in the rotor seal. The dottedcircle represents the sample inlet port 162 in the rotor and rotor seal(not shown) of the valve 76 and which is movable therewith. The samplingvalve 76 may be pneumatically actuated and controlled by using a 4-waysolenoid-actuated valve (not shown) which is electrically connected bysuitable connections to the microprocessor 85. An example of a suitablesampling valve is the Rheodyne Model 7126 Automatic Sampling Injectormanufactured by Rheodyne Incorporated, Cotati, Calif. Other suitablevalves or valve arrangements may be used so long as any such valves orvalve arrangements will function to provide for the loading a sampleloop with a sample, flushing of the chromatographic column and injectingthe sample into the chromatographic column by the carrier liquid asdescribed below.

As shown in FIG. 2, one end of the sample loop 78 is connected to theport 146 of the sampling valve 76, and the other end to the port 152.The carrier fluid infeed line 140 is connected to the port 154. Thewaste line 128 is connected to the port 148 and a second waste line 164is connected to the port 150. The waste lines 128 and 164 join togetherto form a common waste line 168 which is connected to a waste receptacle130. The line 132 to the chromatographic column 82 is connected to theport 156 of the sampling valve 76. The chromatographic column isconnected by a line 170 to the ultraviolet detector 84, the outlet ofwhich is connected by a line 172 to the waste receptacle 130.

In the deactive position of the sampling valve 76 in which the sampleflows through the sample loop 78, the ports of the valve are positionedas shown in FIG. 2. In this deactive position, the sample inlet port162, to which the sample infeed conduit 126 is connected, communicateswith the port 146 in stator of the sampling valve 76 to which one end ofthe sample loop 78 is attached. The connecting passage 158 in the valve76 provides communication between the port 152 to which the other end ofthe sample loop 76 is connected and the port 150 to which the waste line164 is connected. Accordingly, in the deactive position of the samplingvalve 76, the liquid sample stream from the pump 74 flows into the valve76 from the line 126 through the inlet port 162, exits the valve throughthe port 146, passes through the sample loop 78 and flows back into thevalve 76 through port 152. The liquid sample stream then passes throughpassageway 158 in the valve 76, out of the valve 76 through port 150,and into the waste lines 164 and 168 to the waste receptacle 130.

Additionally, when the sampling valve 76 in its deactive position, thecarrier fluid passes from the carrier feed line 140 into port 154 of thevalve 76, and then through the passageway 160 in the valve rotor and outthrough port 156 of the valve 76 into the line 132 which is connected tothe chromatographic column 82. Thus, in the deactive position of thevalve 76, the carrier fluid passes through the valve 76 directly to thechromatographic column 82 and then through the ultraviolet detector 84to the waste receptacle 130. This serves to flush the chromatographiccolumn 82 and detector 84 prior to the next analysis.

The chromatographic column 82 may be any commercially available standardhigh performance ion chromatographic column which will separate thebromide ions from the excess hydrazine reagent and from the largeconcentration of chloride ions. One suitable chromatographic column isthe IONPAC® AS10 Analytical Column manufactured by DIONEX Corporation ofSunnyvale, Calif.

The ultraviolet detector 84 may be any standard commercially availableultraviolet detector which is capable of use with liquids. An example ofone such detector is the ISCO® Model No. 229 UV/Visible detector byIsco, Inc. The detector is set to operate on a wavelength of 210nanometers which is the frequency at which the bromide ion absorbssubstantially more light than hydrazine and the chloride ion. Themeasurement of the bromide ion as a function of the bromine possiblypresent in the chlorine sample taken from the process stream is carriedout through calculations by the microprocessor 85 and is transmitted tothe data acquisition network 20.

The timing sequence for the analytical cycle may be programmed into themicroprocessor 85. At the start of the cycle, the microprocessor 85sends a command to actuate the sampling valve 76 into its activatedposition. FIG. 3 shows the relationship of the ports and passages of thesampling valve 76 when the valve 76 has been actuated into its activatedposition. As shown, the rotor and rotor seal of the valve 76 has beenmoved, moving the passages 158 and 160 relative to the stator so thatpassage 158 interconnects the ports 152 and 154. Passageway 160interconnects the ports 146 and 156. The sample inlet port 162 is alsomoved so that in the activated position, it connects with the port 148.

With this arrangement, the carrier fluid passes from the line 140 intothe port 154 in the valve 76 through passage 158, out through the port152 and through the sample loop 78. The carrier fluid carriers thesample in the sample loop 78 into the valve 76 through the port 146,through the passage 160 and out through the port 156 into the line 132to the chromatographic column 82. The chlorine sample flow from thesample input line 126 enters the inlet port 162 of the valve 76 andflows out of the valve 76 through port 148 and into the waste lines 128and 168 to the waste receptacle 130.

As the sample from the sample loop 78 being carried by the carrier fluidpasses through the chromatographic column 82, the bromide ions areseparated from the hydrazine and chloride ions. The chloride ions andhydrazine elution occurs first, followed by the elution of the bromideions. The chloride ions and hydrazine exit the column 82 first, followedby the bromide ions, and pass to the detector 84 in this order. Thedetector 84 passes an ultraviolet light through the sample-passingthrough the chamber of the detector. The ultraviolet light is absorbedby the ions, causing the excitation thereof, and generating a current.This current is proportional to the amount of ions present. This currentflow is passed to the microprocessor 85 which converts this currentsignal to a reading indicative of the bromine present in the sample. Ata given point in time after the sample has been carried from the sampleloop 78 by the carrier stream to the chromatographic column, the valve76 is actuated in response to a command from the microprocessor 85 backinto its deactive position permitting sample from the incoming samplefeed line 126 to flow through the sample loop 78 ready for the nextanalysis.

While not specifically shown in the drawings, the reaction zone 66, thecarrier fluid source 80, the sampling valve 76, the sample loop 78,chromatographic column 82 and detector 84, as well as the associatedpiping are all temperature controlled. This ensures that there will beno variations in temperature after the system has been calibrated whichwould effect their accuracy of the readings from one analysis toanother.

The initial calibration may be achieved by passing a calibrationchlorine sample containing a known amount of bromine into the reactionzone. The sampling valve is activated with the detector 84 set at thewave length at which the bromide ions are detected and measured. Giventhe flow rates of the chlorine sample, the hydrazine, and the carrierfluid, which will remain constant from one analytical cycle to another,the time is noted for the carrier fluid to carry the sample from thesample loop 78 to the chromatographic column 82 and for the elution ofthe bromide ions and passage thereof through the detector. Thisinformation may be used to set the timing of the analytical cycle. Thereading of the microprocessor calculated from the detector signal whenthe calibration sample is passing therethrough is adjusted to reflectthe true amount of bromine in the sample. This provides a set point forthe other concentrations.

By way of example, the analyzer 14 may provide for an incoming flow rateof the chlorine sample of 100 milliliters per minute (ml/min.) Thehydrazine may be in the form of a 2.5% aqueous solution and have a flowrate to the reaction zone of 2 ml/min. The temperature of the reactionmay be maintained at 25° C. The carrier fluid may be a 50 millimolarsolution of potassium chloride (KC1) in water and have a flow rate of1.5 ml/min. The chromatographic column as mentioned above may be aIONPAC® AS-10 which may be maintained at 40° C. The detector may be anultraviolet detector set at 210 nanometers.

With this arrangement, the analysis cycle will be about 400 seconds. Thesampling valve 76 is switched to its activated position at the start ofthe cycle at a time equal to zero seconds. The chloride ion andhydrazine reagent elution will occur at a point between about 80 secondsand 150 seconds into the cycle. The bromide ion elution will occurbetween about 200 and 350 seconds into the cycle. The chlorine samplewill have been removed from the sample loop 76 at a time prior to theelution of any of the components so that the sampling valve 76 may bereturned to its inactive position as early as 50 seconds into the cycleto feed a new stream of chlorine sample into the sample loop 78. Thestart of the next cycle should be delayed for at least 400 seconds(about 50 seconds after the elution of the bromide ion) so there will bea sufficient period of time after which all components of the samplewill have passed through the detector for the carrier fluid to purge thechromatographic column and the detector before they receive the nextsample.

The non-condensable gases in chlorine analyzer is schematically shown inFIG. 4. This analyzer provides for the detection and analysis ofnon-condensable gases, usually oxygen, nitrogen and carbon dioxide, byan analytical chromatographic scheme.

In accordance with the arrangement shown in FIG. 4, the sample feed line48 containing a flow of the gaseous chlorine from the vaporizer 12 isconnected to one port 200 of a sample cut-off valve 202. This valve 202may be any suitable type of electrically controlled, on-off valve andwhich can be controlled by a microprocessor 203. Preferably, the valve202 is a modified six-port slider plate valve which is pneumaticallyactuated between a deactive position and an activated position. Asolenoid valve (not shown), controlled by the microprocessor 203, maycontrol the supply of pneumatic fluid such as instrument air to thevalve 202 to cause the movement of the valve between its two positions.

The valve 202 is modified by eliminating or blocking the series of portswhich are normally on one side of the valve (the top side as view inFIG. 4). Also, of the three ports 200, 204 and 206 on the other side,the port 206 is blocked as indicated. This, in effect, leaves two activeports 200 and 204.

A moveable slider plate 208 within the valve 202 has a groove or passage210 therein which interconnects the two ports 200 and 204 when the valve202 is in its deactive position as shown by the solid lines in thedrawing. When the valve 202 is actuated into its activated position, theslider plate 208 is moved into the off-position as shown by the dottedlines in the drawing, wherein the passage 210 is out of alignment withthe port 200 and there is no communication, and thus, no flow betweenports 200 and 204.

One end of a sample in-feed line 212 is connected to the port 204 of thevalve 202. The other end of the sample infeed line 212 is connected to asampling valve 214.

The sampling valve 214 may be a standard 8-port commercially availableslider plate valve which is pneumatically actuated between a deactive orsample loading position and an activated or sample injecting position. Asolenoid valve (not shown), controlled by the microprocessor 203, maycontrol the supply of the pneumatic fluid such as instrument air to thevalve 214 to cause the movement of the valve between its two positions.

The sampling valve 214 may include a slider plate 216 movable in a body218 between the two positions of the valve. The slider plate 216 mayinclude a first groove or passage 220 which extends axially in the topsurface of the slider plate 216 as viewed in FIG. 4. A second groove orpassage 222 may extend axially in the bottom surface of the slider plate216. A through-bore or passage 224 extends between the top and bottomsurfaces of the slider plate 216.

The body 218 of the sampling valve 214 may include six ports 226, 228,230, 232, 234 and 236, with the ports 226, 228 and 230 being positionedin the top surface of the body and the ports 232, 234 and 236 beingpositioned in the bottom surface of the body 218 when the valve isorientated as shown in FIG. 4.

When the sampling valve 214 is in its deactive or loading position, theslider plate 216 is positioned as shown by the solid lines in FIG. 4. Inthe deactive or loading position, the passage 220 connects the ports 226and 228, while passage 222 connects the ports 232 and 234. The throughbore or passage 224 in the slider plate 216 connects the ports 230 and236. When the valve 214 is actuated into its activated, or injectingposition, the slider plate 216 is moved to the right as viewed in FIG.4, assuming the position indicated by the dotted lines. In the activatedor injecting position, the passage 220 connects the ports 228 and 230and passageway 222 connects the ports 234 and 236. The ports 226 and 232are blocked and the through-bore or passage 224 is not active.

The sample infeed line 212 from the sample cut-off valve 202 isconnected to port 232 of the sampling valve 214. The sample return line54 with the flow meter 58 therein is connected to port 226. A sampleloop 238 has one end 240 connected to port 228 and its other end 242connected to port 234. A sample outlet line 244 is connected to port 236and a carrier stream line 246 is connected to port 230.

The sample outlet line 244 from the sampling valve 214 includes a firstchromatographic column 248 therein. This column 248 serves to separatethe oxygen and nitrogen as bulk from the chlorine and carbon dioxide.One suitable type of chromatographic column may be an oil impregnateddiatomaceous earth material packed in a tubular column. By way ofexample, the preferred column is a 10 foot length of 1/4 inch tubingpacked with Chromosorb® W material (a diatomaceous silica) which isimpregnated with 15% by weight SF-96, a silicon oil. Chromosorb® is atrademark of Manville Products.

The sample outlet line 244 containing the first chromatographic column248 is connected to a backflush valve 250. The backflush valve 250 maybe a standard commercially available eight port slider plate valve whichis pneumatically actuated between a deactive position and an activatedposition. An electrically operated solenoid valve (not shown) may beused to control the supply of pneumatic fluid such as instrument air tothe valve 250 to cause the actuation of the backflush valve 250 betweenits two positions. The solenoid valve may in turn be controlled by themicroprocessor 203.

In general, the backflush valve 250 includes a valve body 252 havingeight ports 254, 256, 258, 260, 262, 264, 266 and 268 therein. A sliderplate 270 is slidably mounted in the body 252 for movement between thedeactivate and activated positions of the valve 250. The slider plate270 includes two grooves or passages 272 and 274 in its upper surface(as viewed in FIG. 4) and two grooves or passages 276 and 278 in itsbottom surface. A through-bore or passage 279 extends between the upperand lower surfaces of the slider plate 270 as shown.

In the deactive position of the backflush valve 250, in which the sliderplate 270 is positioned in its retracted position as shown by the solidlines in FIG. 4, the passage 272 is aligned only with the port 254,thereby effectively blocking the port 254. The passage 274 connects theports 256 and 258. The passage 276 is aligned only with the port 262,thereby effectively blocking the port 262. The passage 278 connects theports 264 and 266 and the through-bore or passage 279 connects the ports260 and 268.

In the activated position of the backflush valve 250, the slider plate270 is extended to the right as viewed in FIG. 4 into the positionindicated by the dotted lines. In this position, the passage 272interconnects the ports 254 and 256 and passage 274 interconnects theports 258 and 260. Also, in the activated position, the passage 276interconnects the ports 262 and 264 and the passage 278 interconnectsthe ports 266 and 268. The through-bore or passage 279 is inactive inthis position of the valve 250.

The sample outlet line 244 from the sampling valve 214 containing thefirst chromatographic column 248 is connected to the port 264 of thebackflush valve 250. A sample feed line 280 is attached to the port 266.A loop 282, containing an adjustable flow restrictor 284 has one endconnected to port 260 and its other end connected to the port 268.

A source 286 of a carrier gas may be connected to a carrier gas infeedline 288 which is split into a first carrier gas stream line 290 and asecond carrier gas stream line 292. The carrier gas infeed line 288 mayinclude a pressure regulator 294 to control the pressure of the incomingcarrier gas, and a pressure gauge 296 to provide an indication of thepressure. The carrier gas may be any suitable type of gas which will notreact with any components of the sample stream, does not contain any ofthe components for which the analysis is being conducted, and will notinterfere with the detection of the components by the detector.Specifically, the carrier gas may be a suitable inert gas and ispreferably highly purified helium gas which may be provided in asuitable storage tank 298.

The first carrier gas stream line 290 is connected to the port 258 ofthe backflush valve 250 and the second carrier gas stream line 292 isconnected to the port 262. A waste chlorine discharge line 300 isconnected to the port 254 of the backflush valve 250 for dischargingwaste chlorine to a suitable scrubber 302.

The sample feed line 280 from the backflush valve 250 includes a secondchromatographic column 304 therein. This column 304 serves to separatethe oxygen and nitrogen from the carbon dioxide. The column 304 may bein the form of coiled tubing packed with a polymer. In the preferredform, the column is a 10 foot length of coiled 1/4 inch tubing packedwith HayeSep® R powder, a polymeric powder. Such powders arecommercially available from Alltech Associates, Inc. of Deerfield, Ill.HayeSep® is a trademark of Hayes Separation, Inc.

The end of the sample feed line 280 opposite the backflush valve 250 isconnected to a storage valve 306. The storage valve 306 may be astandard, commercially available, eight port slider plate valve similarto the valve 250 and which is pneumatically actuated between a deactiveposition and an activated position. An electrically operated solenoidvalve (not shown) may be used to control the supply of pneumatic fluidsuch as instrument air to the valve 306 to cause the actuation of thevalve between its two positions. The solenoid valve is in turncontrolled by the microprocessor 203.

In general, the storage valve 306 includes a valve body 308 having eightports 310, 312, 314, 316, 318, 320, 322 and 324 therein. A slider plate326 is slidable mounted in the body 308 for movement between theactivated and inactive positions of the valve 306. The slider plate 326includes two grooves or passages 328 and 330 in its upper surface (asviewed in FIG. 4) and two grooves or passages 332 and 334 in its bottomsurface. A through-bore or passage 335 extends between the upper andlower surfaces of the slider plate 326 as shown.

In the deactive position of the valve 306, in which the slider plate 326is positioned in its retracted position as shown by the solid lines inFIG. 4, the passage 328 is aligned only with the port 310. The passage330 connects the ports 312 and 314. The passage 332 is aligned only withthe port 318. The passage 334 connects the ports 320 and 322, and thethrough-bore or passage 335 connects the ports 316 and 324. The ports310 and 318 may be permanently closed by plugs 336 or other suitablemeans so that they are rendered inactive in both positions of thestorage valve 306. While an eight port valve is used in the preferredembodiment, other types of valves such as a six port slider plate valvemay be used.

In the activated position of the storage valve 306, the slider plate 326is extended to the right as viewed in FIG. 4 into the position indicatedby the dotted lines. In this position, the passage 328 interconnects theports 310 and 312 and the passage 330 interconnects the ports 314 and316. Also, in the activated position, the passage 332 interconnects theports 318 and 320 and the passage 334 interconnects the ports 322 and324. The through-bore or passage 279 is inactive in this position of thevalve 250. Additionally, as the ports 310 and 318 are plugged, the ports312 and 320 are blocked in the activated position of the valve 306,thereby blocking off or isolating the molecular sieve column 346.

The sample feed line 280, connected at one end to the backflush valve250 and containing the second chromatographic column 304, is attached atits other end to the port 314 of the storage valve 306. A carrier-sampleflow line 338 leading to a detector 339 is attached to the port 322 ofthe storage valve 306. A loop 340, containing an adjustable flowrestrictor 342, has one end connected to the port 316 of the storagevalve 306 and its other end connected to the port 324. A storage loop344 containing a third chromatographic column in the form of a molecularsieve column 346 has one end connected to port 312 of the storage valve306 and its other end connected to port 320.

The molecular sieve column 346 functions to separate the oxygen andnitrogen which are temporarily stored in the loop 344 as will beexplained below. The molecular sieve may be any suitable materialcapable of achieving the desired separation of the oxygen and nitrogenand preferably is a 5 Å (Angstrom) sieve contained in a 10 foot lengthof coiled 1/4 inch tubing.

The carrier-sample flow line 338 from the port 322 of the storage valve306 is connected to the discharge ionization detector 339 for supplyingthe sample to the detector for analysis. The sample passes from thedetector to a waste line 348 which leads to a caustic scrubber 350 fordisposal of the sample material.

The detector 339 is preferably a discharge ionization detectorcontaining its own power control. Any suitable commercially availabledischarge ionization detector may be used. An example of one suchdetector is Model 24-600 sold by Gow-Mac Instrument Co. The detector 339sends an electrical signal proportional to the level of a particularcomponent of the sample stream being analyzed to the microprocessor 203which converts the signal into a reading indicative of the level of thatparticular component. The microprocessor 203 sends the information abouta particular component to the common data acquisition network 20 forprocessing.

In operation, the sample cut-off valve 202, the sampling valve 214, thebackflush valve 250 and the storage valve 306 are maintained in theirdeactive positions until it is desired to begin an analysis. Theoperation of the analysis cycle is controlled by the microprocessor 203.

In the deactive positions of the valves 202, 214, 250 and 306, thechlorine sample in gaseous form from the vaporizer 12 flows into thesample cut-off valve 202 through port 200, flows through passage 210 andout of the cut-off valve 202 through the port 204 into the feed line 212leading to the sampling valve 214.

The gaseous chlorine sample enters the sampling valve 214 from the feedline 212 through port 232, passes through passage 222 and exits thevalve 214 through port 222 into the sample loop 238. From the sampleloop 238, the gaseous chlorine sample is returned to the valve 214through port 228, passes through passageway 220 and exits the valve 214through port 226 into the return line 54 wherein the sample is fed backinto the process stream.

Also during the deactive period, a first carrier gas stream from thecarrier gas storage tank 298 flows from the tank 298 through line 288and the first carrier gas stream line 290 to the port 258 of thebackflush valve 250 where it passes through the passage 274 and exitsthe valve 250 through the port 256. The first carrier gas stream thenflows through the line 246 to the sampling valve 214, where it entersthe port 230, passes through the passage 224 and exits the valve 214through the port 236 into the line 244 containing the firstchromatographic column 248. The first carrier gas stream then flowsthrough the first chromatographic column 248 and returns to thebackflush valve 250 where it enters the valve 250 through the port 264,passes through passage 278 and exits the valve 250 through the port 266into the line 280 containing the second chromatographic column 304.

The first carrier gas stream then passes through the secondchromatographic column 304 and enters the storage valve 306 through theport 314. In the valve 306, the first carrier gas stream passes throughpassage 330, exits the valve 306 through port 312 and passes through theloop 344 containing the molecular sieve column 346 and reenters thevalve 306 through port 320. The first carrier gas stream then passesthrough passage 334 in the valve 306 and exits the valve 306 through theport 322 into the carrier-sample flow line 338 through which it flows tothe detector 339 and exits the detector into the waste line 348 to thecaustic scrubber 350.

Thus, in the deactive or loading position of the analyzer 16, a gaseouschlorine sample from the process stream which has been converted togaseous form by the vaporizer 12, continuously flows through the sampleloop 238 and back to the process stream. At the same time, the firstcarrier gas stream passes through the two chromatographic columns 248and 304, the molecular sieve column 346 and the detector 339. This flowof carrier fluid serves to purge the chromatographic columns 248 and304, the molecular sieve column 346 and the detector 339 of any sampleremaining from the previous analysis. As will be noted, in the deactiveposition of the valves, the flow of the second carrier gas stream in theline 292 is blocked or cut off by the backflush valve 250.

When it is desired to perform an analysis, immediately prior thereto,the sample cut-off valve 202, under the control of microprocessor 203,is actuated into its activated position which serves to cut off the flowof gaseous chlorine sample to the sampling valve 214. This permits thegaseous chlorine sample in the sample loop to depressurize. After ashort period of time sufficient to accomplish the depressurization, thesampling valve 214 is actuated into its activated position to start theanalysis, while the backflush valve 250 and storage valve 306 remain intheir deactive positions. The position of the valves 202, 214, 250 and306 at this stage of the analysis is shown in FIG. 5.

With the valves 202, 214, 250 and 306 positioned as shown in FIG. 5, thefirst carrier gas stream in line 246 enters port 230 of the samplingvalve 214, passes through passage 220, exits port 228 and passes throughthe sample loop 238, carrying with it the chlorine sample in the loop238. The first carrier gas stream transports the chlorine sample fromthe loop 238 back into the valve 214 through the port 234, and thenthrough the passage 222, and out through the port 236 of the valve 214into the line 244 containing the first chromatographic column 248. Thecarrier gas continues to transport sample from the first chromatographiccolumn 248 through the backflush valve 250 by way of the port 264 andthe passage 278 and out through the port 266 into the line 280containing the second chromatographic column 304. The first carrier gasstream with sample continues into the storage valve 306 through port314, passes through the passage 330 and exits the valve 306 through theport 312 into the storage loop 344 containing the molecular sieve column346. From the storage loop 344, the carrier gas continues back into thestorage valve 306 through the port 320, passes through the passage 334,and exits the valve 306 through the port 322 into line 338 where thecarrier gas passes through the detector 339 and then to the line 348 tothe caustic scrubber 350.

During the passage of the first carrier gas stream and sample throughthe first chromatographic column 248, the column 248 serves to separatethe chlorine from the other gases, specifically oxygen, nitrogen andcarbon dioxide, with the oxygen and nitrogen being separated as bulkfrom the chlorine and carbon dioxide. Chlorine, being the heaviestmaterial is never allowed to exit the first chromatographic column 248.The oxygen and nitrogen, being the lightest, pass through the column 248first, followed by the carbon dioxide, and into the secondchromatographic column 304 where the separation of the oxygen andnitrogen from the carbon dioxide is completed. The oxygen and nitrogenfrom the second chromatographic column 304 are allowed to enter themolecular sieve column 346 by passing through the port 314 of thestorage valve 306, passing through the passage 330, and exiting thevalve 306 through the port 312 into the loop 344 containing themolecular sieve column 346. As soon as the oxygen and nitrogen enterinto the molecular sieve column 346, the storage valve 306 is moved intoits activated position. The position of the valves 202, 214, 250 and 306after the storage valve 306 is activated is shown in FIG. 6.

As shown in FIG. 6, by this stage of the analysis, the sample cut-offvalve 202 and the sampling valve 214 may be returned to their inactivepositions. The backflush valve 250 remains in its inactive position andthe storage valve 306 has been actuated into its activated position.When the storage valve 306 is activated, the ports 312 and 320 of thevalve 306 are effectively blocked since the passages 328 and 332 in theslider plate 308 now provide communication between the port 312 and ablocked port 310 and the passage 332 provides communication between port320 and blocked port 318. This serves to trap the oxygen and nitrogen inthe molecular sieve column 346.

The activation of the storage valve 306 also results in the firstcarrier gas stream with the sample flowing in line 280 from the secondchromatographic column into port 314 of the storage valve 306 beingdiverted so that it flows through passage 330 in the valve 306, out ofthe valve 306 through port 316, through the restrictor 342 and back intothe valve 306 through port 324. The first carrier gas stream with samplethen passes through passage 334 and exits the valve 306 through port 322into line 338 to the detector.

After the storage valve 306 is activated, and as soon as all the carbondioxide is carried out of the first chromatographic column 248 and intothe second chromatographic column 304, the backflush valve 250 isactivated while the sample cut-off valve 202 and the sampling valve 214remain deactive, so that the valves assume the positions as shown inFIG. 7. In this position of the valves 202, 214, 250 and 306, the firstcarrier gas stream from line 290 is caused to bypass the sampling valve214 and the first chromatographic column 248, and pass through therestrictor 284 associated with the backflush valve 250, through thesecond chromatographic column 304, through the restrictor 342 associatedwith the storage valve 306 to the detector 339 to carry the carbondioxide from the second chromatographic column 304 to the detector 339for measurement by the detector 339 as the first component of thesample.

As will be seen from FIG. 7, this is achieved by the fact that uponactivation of the backflush valve 250, the first carrier gas streamenters the backflush valve 250 through port 258 from line 290 and isdiverted by the passage 274 to the port 260 from which its exits intothe loop 282 containing the restrictor 284. From the restrictor 284, thesecond carrier gas stream reenters the valve 250 through port 268,passes through passage 278 and exits the valve 250 through port 266 intothe line 280 containing the second chromatographic column 304. Afterpassing through the second chromatographic column 304 and carrying withit the carbon dioxide in the column 304, the first carrier gas streamenters the storage valve 306 through port 314, passes along the passage330, and exits the valve 306 through the port 316 into the restrictorline 340 containing the restrictor 342. After passing through therestrictor 342, the first carrier gas stream containing the carbondioxide to be measured reenters the valve 306 through the port 324,passes through passage 334 and exits the valve 306 through port 322 intothe line 338 to the detector 339. As the sample passes through thedetector 339, the detector generates an electrical signal proportionalto the amount of carbon dioxide present in the sample which is fed tothe microprocessor 203. The microprocessor 203 converts the electricalsignal from the detector 339 into a signal indicative of the actuallevel of carbon dioxide. This signal may then be fed to the dataacquisition network 20 for recording and display.

The restrictor 284 associated with the backflush valve 252 serves toreduce the flow rate of the first carrier gas stream to the secondchromatographic column 304 when the backflush valve 250 is in itsactivated position. This is necessary since the first carrier gas streamis under a sufficiently high pressure from its source so it will have aflow rate sufficient to overcome the resistance to flow of the firstchromatographic column 248 when the backflush valve 250 is deactive andthe carrier stream passes through the first column. Since the firstcarrier gas stream bypasses the first chromatographic column 248 whenthe backflush valve 250 is activated, the flow rate of the first carriergas stream must be reduced an amount substantially the same as it wouldbe by the chromatographic column 248 or the flow rate of the firstcarrier gas stream will be too high as it passes through the secondchromatographic 304 and ultimately through the detector 339 to permit anaccurate measurement. Accordingly, the restrictor 284 should be set toprovide a reduction in flow rate of the first carrier gas streamsubstantially equivalent to the reduction which is caused by the firstchromatographic column.

In a similar manner, the flow restrictor 342 in the loop 340 connectedto the storage valve 306 serves to reduce the flow rate of the firstcarrier gas stream when the storage valve 306 is in its activatedposition and the first carrier gas stream bypasses the molecular sievecolumn 346. The flow restrictor 342 should be set so that the flow rateof the first carrier gas stream entering line 338 from the valve 306 isthe same when it bypasses the molecular sieve column 346 as it is whenit passes through the molecular sieve column 346. Thus, the flowrestrictors 284 and 342 serve to maintain the flow rate of the firstcarrier gas stream to the detector 339 at a constant rate whether thefirst carrier gas stream passes through the first chromatographic column248 and the molecular sieve column 346 or whether it bypasses one orboth of them.

Additionally, when the backflush valve is activated, as shown in FIG. 7,the second carrier gas stream flows through line 292 to the backflushvalve 250 and enters the valve 250 through the port 262. The secondcarrier gas stream then passes through passage 276 in the backflushvalve 250 and out of the valve 250 through the port 264. The secondcarrier gas stream then flows backward in the line 244 through the firstchromatographic column 248 and carries the chlorine in the column 248with it into port 236 of the sampling valve 214. The second carrier gasstream along with the chlorine that was present in the firstchromatographic column 248 then passes through the through-bore 224 inthe valve 1214 and exits through port 230 into the line 246. The secondcarrier gas stream and the chlorine enter the port 256 of the valve 250from the line 246, pass through the passage 272 and exit the valve 250through the port 254 into line 300 to the caustic scrubber 302. Thus,when the backflush valve 250 is actuated, the first chromatographiccolumn 248 is backflushed to remove the chlorine therefrom and carry itout of the system to the caustic scrubber 302.

After the measuring and recording of the carbon dioxide level by thedetector 339, the storage valve 306 is deactivated while the backflushvalve 250 is maintained in its activated position. The valves 202, 214,250 and 306 at this stage are in the positions as shown in FIG. 8. Asmay be seen from FIG. 8, the first carrier gas stream continues to flowthrough the restrictor 284 associated with the backflush valve 250 andthe second chromatographic column 304 and enters the storage valve 306through the port 314. With the storage valve 306 now in its deactiveposition, the first carrier gas stream then passes through the passage330 and out through port 312 of the valve 306 into the line 344containing the molecular sieve column 346. The carrier gas passesthrough the molecular sieve column 346, carrying the oxygen andnitrogen, which now have been completely separated by the column 346,back into the valve 306 through the port 320. The first carrier gasstream carrying the oxygen and nitrogen then passes through passage 334of the valve 306 and out of the valve 306 through port 322 into the line338 in which the oxygen and nitrogen are carried to the detector 339 formeasurement as components two and three of the sample, respectively.After the measuring of the oxygen and nitrogen, the backflush valve 250may be deactivated, resulting in all the valves 202, 214, 250 and 306being in their deactive positions as shown in FIG. 4, ready for anotheranalysis by repeating the analytical cycle described above.

While not specifically shown in the drawings, the various valves 202,214, 250 and 306, the carrier fluid source 286, the sample loop 238, thechromatographic columns 248 and 304, the molecular sieve column 346 anddetector 339, as well as the associated piping, are all maintained in atemperature controlled environment with the appropriate temperaturebeing maintained by suitable heating means such as a forced air orelectric heater. This ensures that there will not be any variations intemperature after the system has been calibrated which would effecttheir accuracy of the readings from one analysis to another.

The timing of the actuation of the individual valves between theirdeactive and activated positions may be determined experimentally uponinitial calibration of the analyzer 16. Such initial calibration may beachieved introducing a calibration chlorine sample containing a knownamount of the non-condensable gases into the sample loop and startingthe cycle. The time at which the various gases elute from the variouscolumn combinations and are passed to the detector 339 is noted and theactuation of the various valves 202, 214, 250 and 306 set accordingly toachieve the complete separation of the components. By using a sample ofa known quantity of the various non-condensable gases, themicroprocessor may be adjusted to reflect the actual concentration ofeach individual component of the sample which will provide the setpoints for the other concentrations.

By way of example, the system as shown in FIGS. 4-8 may be operatedusing a 10 foot length of 1/4" tubing of 15% SF-96 on Chromosorb® W forthe first chromatographic column 248, a 10 foot length of 1/4' tubingcontaining HayeSep® R powder as the second chromatographic column, and a10 foot length of 1/4" tubing containing a 5 Å molecular sieve as themolecular sieve column 346. The chromatographic columns 248 and 304, andthe molecular sieve column 346 may be maintained at a temperature of 75°C. The carrier gas may be high purity helium having a flow rate of 50ml/min. The detector may be a Model 24-600 discharge ionization detectoras described above.

With the arrangement as described immediately above, the analyticalcycle is about 1500 seconds. Assuming that the cycle starts when thesampling valve 214 is actuated into its activated position, the samplecut-off valve 202 is first actuated about 25 seconds before the actualstart of the cycle. This permits time for the sample in the sample loop238 to depressurize. After approximately 25 seconds, at a time equalzero, the sampling valve 214 is actuated to start the cycle. After about10 seconds into the cycle, giving time for the carrier gas stream toremove the sample from the sample loop 238, the sampling valve 214 ismoved back into its deactive position followed by the actuation of thesample cut-off valve 202 into its deactive position at about 15 secondsinto the cycle. The exact time point for actuating the sample cut-offvalve 202 and the sampling valve 214 back into their deactive positionsis not critical so long as the sampling valve 214 is deactivated priorto the activation of the backflush valve 250. The sampling valve 214should preferably be moved to its inactive position slightly prior tothe actuation of the cut-off valve 202 into its deactive position sothat the sample from the cut-off valve 202 will have a path through thesample valve 214.

The storage valve 306 is actuated into its activated position at about245 seconds into the cycle. The elution of the carbon dioxide occursbetween about 250 and 545 seconds into the cycle so that the backflushvalve 250 is actuated into its activated position at about 550 seconds.The storage valve 306 is then actuated into its deactive positionopening the storage loop 344 to the carrier fluid at about 613 seconds.The oxygen elution occurs between about 620 and 818 seconds into thecycle and nitrogen elution occurs between about 825 and 1090 seconds.The backflush valve 250 may be actuated into its deactive position atabout 1470 seconds into a position to start the next cycle.

The halocarbon in chlorine analyzer 18, shown schematically in FIGS.9-11, is adapted to measure chlorinated hydrocarbons which may bepresent in the chlorine sample, and specifically methylene chloride,chloroform and carbon tetrachloride. All other chlorinated hydrocarbonswhich could be potentially present in the chlorine sample are measuredas a group.

The halocarbon in chlorine analyzer 18 includes generally a samplecut-off valve 400 for cutting off the supply of chlorine sample from theprocess stream, a sampling valve 402 for feeding the sample from theprocess stream to a sample loop 404, a backflush valve 406 forcontrolling the flow of a carrier gas, a diverter valve 408 fordiverting the chlorine to prevent its passage to the detector, achromatographic column 410 for separating the components of the samplestream, a detector 412 for detecting and measuring the desiredcomponents of the sample, and a microprocessor 414 for controlling thetiming of the analytical cycle and converting the signals from thedetector 412 into readable output.

Specifically, referring to FIG. 9, the chlorine sample enters theanalyzer through the line 50 and valve 52 into a port 415 of the cut-offvalve 400. The cut-off valve 400 may be of any type of electricallyactuated, on-off valve that may be controlled by the microprocessor 414.Preferably, the valve 400 is a modified pneumatically operated six-portslider plate valve controlled by a solenoid valve (not shown) and issimilar to the cut-off valve 202 described in connection with theanalyzer shown in FIGS. 4-8. The valve 400 includes two active ports 415and 416, and a blocked port 418. A moveable slider plate 420 within thevalve 400 has a groove or passage 422 which interconnects the port 415with the port 416 when the valve 0 is in its deactive position asindicated by the solid lines in the drawing. When the valve 400 isactivated, the slider plate 420 is moved into the off-position shown bythe dotted lines in the drawing, wherein the passage 422 is out ofalignment with the port 415 and there is no communication, and thus, noflow between the ports 415 and 416.

The port 416 of the valve 400 has one end of a sample in-feed line 424connected thereto. The other end of the sample infeed line 424 isconnected to the sampling valve 402.

The sampling valve 402 may be similar to the sampling valve 214 shownand described in connection with the non-condensable gas in chlorineanalyzer 16 of FIGS. 4-8. The sampling valve 402 may be a standard,commercially available, 6-port sliding plate valve which ispneumatically actuated between a deactive or sample loading position andan activated or sample injecting position. A solenoid valve (not shown),controlled by the microprocessor 414, may control the supply of thepneumatic fluid such as instrument air to the valve 402 to cause themovement of the valve 402 between its two positions.

The sampling valve 402 may include a slider plate 426 movable in a body428 between the two positions of the valve 2. The slider plate 426 mayinclude a first groove or passage 430 which extends axially in the topsurface of the slider plate 426 as viewed in FIG. 9. A second groove orpassage 432 may extend axially in the bottom surface of the slider plate426. A through-bore or passage 434 is provided in the slider plate 426extending between the top and bottom surfaces thereof.

The body 428 of the sampling valve 402 may include six ports 436, 438,440, 442, 444 and 446, with ports 436, 438 and 440 being positioned inthe top surface of the body 428 and ports 442, 444 and 446 beingpositioned in the bottom surface of the body 428 when the valve 402 isspatially positioned as shown in FIG. 9.

The deactive or loading position of the sampling valve 402 is indicatedby the solid lines of the slider plate 426 as shown in FIG. 9 and theactivated, or injecting position by the dotted lines of the slider plate426. In the deactive or loading position, the passage 430 connects theports 436 and 438, while passage 432 connects the ports 442 and 444. Thethrough-bore or passageway 434 connects the ports 440 and 446. When thevalve 402 is activated, the slider plate 426 is moved to the right asviewed in FIG. 9 into the activated or injecting position, assuming theposition indicated by the dotted lines. In the activated or injectingposition of the valve 402, the passage 430 connects the ports 438 and440 and the passage 432 connects the ports 444 and 446, while the ports436 and 442 are blocked. The through-bore 434 is not active in theactivated position of the sampling valve 404.

The sample infeed line 424 from the sample cut-off valve 400 isconnected to the port 442 of the sampling valve 402. The sample returnline 54 with the flow meter 58 therein is connected to the port 436. Thesample loop 404 has one end 448 connected to the port 438 and its otherend 450 connected to the port 444. A carrier-sample outlet line 452 isconnected to the port 446 of the sampling valve 402 and a first carrierstream line 453 is connected to the port 440.

The carrier-sample outlet line 452, connected at one end to the samplingvalve 402, has its other end connected to the backflush valve 406. Thebackflush valve 406 is a specially modified, pneumatically operated, sixport sliding plate valve which is pneumatically actuated between adeactive and an activated position. An electrically operated solenoidvalve (not shown) may be used to control the supply of pneumatic fluidsuch as instrument air to the valve 406 to cause the actuation of thebackflush valve 406 between its two positions. The solenoid valve may inturn be controlled by the microprocessor 414.

The backflush valve 406 may include a slider plate 454 movable in a body456 between the two positions of the valve. The slider plate 454 mayinclude a first groove or passage 458 which extends axially in the topsurface of the slider plate 454 as view in FIG. 9. A second groove orpassage 460 may extend axially in the bottom surface of the slider plate454. A through-bore or passage 462 is usually provided in the sliderplate 454 extending between the top and bottom surfaces thereof.However, this through-bore 462 is plugged by an insert 464.Alternatively, the slider plate may be fabricated without the through-bore 464.

The body 456 of the backflush valve 406 may include six ports 468, 470,472, 474, 476 and 478, with ports 468, 470 and 472 being positioned inthe top surface of the body 456 and ports 474, 476 and 478 beingpositioned in the bottom surface of the body 456 when the valve 406 isspatially positioned as shown in FIG. 9.

The deactive position of the backflush valve 406 is indicated by thesolid lines of the slider plate 454 in FIG. 9 and the activated positionindicated by the dotted lines of the slider plate 454. In the deactiveposition of the valve 406, the passage 458 connects the ports 468 and470, while passage 460 connects the ports 474 and 476. 7The ports 472and 478 are effectively blocked by the insert 464 in the through-bore orpassage 462. When the valve 406 is activated, the slider plate 454 ismoved to the right as viewed in FIG. 9, assuming the position indicatedby the dotted lines. In this activated position, the passageway 458connects the ports 470 and 472 and the passageway 460 connects the ports476 and 478, while the ports 468 and 474 are blocked. The backflushvalve 406 has thus been modified from the standard configuration so thatalthough it includes the six ports 468, 470, 472, 474, 476 and 478, itonly has two passageways 458 and 460 for providing communication betweenthe ports, resulting in one set of ports 472,478 being rendered inactivein one position of the valve 6 and a second set of ports 468,474 beingrendered inactive in the other position of the valve.

A chromatographic loop 480, containing the chromatographic column 410has one end 482 connected to the port 470 of the backflush valve 6 andits other end 484 connected to the port 476 of the valve 6. Thechromatographic column 410 is one that separates methylene chloride,chloroform and carbon tetrachloride from each other and from thechlorine. The preferred form of the column is a 4 foot length of 1/4inch coiled tubing packed with acid washed Chromosorb® W impregnatedwith 40% Kel-F® oil, a chlorofluorocarbon oil, and maintained at atemperature of 60° C.

A line 486 is attached to a source of a carrier gas. The carrier gas maybe any suitable type of gas which will not react with any of thecomponents in the sample stream, does not contain any of the componentsfor which the analysis is being made, and which does not interfere withthe detection and measurement by the detector or with the separation ofthe components in the chromatographic column 410. More specifically, thecarrier gas may be any suitable inert gas. Preferably, the carrier gasis helium supplied from suitable storage tank 487 to which the line 486is connected.

The line 486 includes a pressure regulator 488 and pressure gauge 490 tocontrol the flow of the helium and provide an indication of itspressure. Preferably, the flow rate of the helium is relatively slow,about 55 milliliters per minute (ml/min). The line 486 branches into twocarrier stream lines, the first carrier gas stream line 453 which isconnected to the port 440 of the sampling valve 402, and a secondcarrier gas stream line 492 which is connected to the port 478 of thebackflush valve 406.

A carrier-sample output line 494 has one end connected to the port 474of the backflush valve 406 and its other end connected to an inlet 496of the diverter valve 408. A reverse flow sample output line 498 has oneend connected to the port 472 and its other end connected to thecarrier-sample output line 494 at a "T" 500 positioned upstream of thediverter valve 408 and adjacent to the port 474 of the backflush valve406.

The diverter valve 408 may be any type of valve which can beelectrically controlled by the microprocessor 414 to divert the flowentering its inlet 496 to either of its two output ports 502 and 504.Preferably, the diverter valve 408 is a solenoid actuated, 3-portsliding plate valve. The output port 502 of the diverter valve 408 isconnected to a line 506 which in turn is connected to the detector 412.The other output port 504 is connected to a line 508 leading to acaustic scrubber 510.

The detector 412 is preferable a flame ionization detector. The detector412 may be any commercially available flame ionization detector capableof detecting and measuring the desired components. An example of onesuch detector is the GOW-MAC FID System Model No. 40-900 by Gow-MacInstrument Co. As is common with such detectors, fuel is supplied to thedetector which in the preferred case may be hydrogen and air. Thehydrogen may be supplied from a suitable source such as a storage tank512 through a line 514 containing a pressure regulator 516 to maintainthe desired pressure and a pressure gauge 518 and flow meter 520 whichprovide an indication of the pressure and flow of the hydrogenrespectively. The air may be supplied to the detector 412 from asuitable source such as available plant air through a line 522containing a pressure regulator 524 to maintain the desired pressure anda pressure gauge 526 and flow meter 528 which provide an indication ofthe pressure and flow of the air respectively.

The flame ionization detector 412 ionizes the separated chemicalcomponents eluting from the chromatographic column 410 and which enterthe detector 412 from line 506. The ionized components collect at acollector plate (not shown) in the detector 412 and a current isgenerated proportional to the amount of the individual component beingdetected. The current-signal is transmitted to the microprocessor 414,which converts the signal into a readable form indicative of theconcentration of the particular component. The microprocessor 414 sendsthe data collected to the common data acquisition network 20 fortabulation and printout. The combusted sample exits the detector 412through an output line 530 to a vent.

In operation, the sample cut-off valve 400, the sampling valve 402 andthe backflush valve 406 are maintained in their deactive positions untilit is desired to begin an analysis. The operation of the analysis cycleis controlled by the microprocessor 414.

In the deactive positions of the valves 400, 402 and 406, the chlorinesample in gaseous form from the vaporizer 12 flows into the samplecut-off valve 400 through port 415, flows through passage 422 and out ofthe cut-off valve 400 through port 416 into the feed line 424 leading tothe sampling valve 402.

The gaseous chlorine sample enters the sampling valve 402 from the feedline 424 through the port 442, passes through the passage 432 and exitsthe valve 402 through the port 444 into the sample loop 404. From thesample loop 404, the gaseous chlorine sample is returned to the valve402 through the port 438, passes through the passage 430 and exits thevalve 402 through the port 436 into the return line 54 wherein thesample is fed back into the process stream at a low pressure point.

Also during the deactive period, a first carrier gas stream from thecarrier gas storage tank 487 flows through the line 486 and the firstcarrier gas stream line 453 to the port 440 of the sampling valve 402where it passes through the passage 434 and exits the valve 402 throughthe port 446 into the line 452 to the backflush valve 406. The firstcarrier gas stream then enters the port 468 of the backflush valve 406,passes through the passage 458 and exits the valve 406 through the port470 into the chromatographic loop 480 containing the chromatographiccolumn 410. The first carrier gas stream then flows through thechromatographic column 410 and returns to the backflush valve 406 whereit enters the valve 406 through port 476. The first carrier gas streamthen passes through the passage 460 and exits the valve 406 through theport 474 into the line 494 to the diverter valve 408. The diverter valve408 at this stage of the analysis is in its inactive position whichprovides for flow through the valve 408 and out through the outlet 502to line 506. The first carrier gas stream passes through the divertervalve 408 into the line 506 through which it flows to the detector 412and then exits the detector 412 into the line 530 to the vent.

Thus, in the deactive or non-detecting position of the valves 400, 402,406 and 408, a gaseous chlorine sample from the process stream which hasbeen vaporized by the vaporizer 12 continuously flows through the sampleloop 4 and back to the process stream. At the same time, am firstcarrier gas stream passes through the chromatographic column 410 and thedetector 412. This flow of carrier gas serves to purge thechromatographic column 410 and detector 412 of any sample remaining fromthe previous analysis. As will be noted, in the deactive position of thevalves, the flow of the second carrier gas stream from the storage tank487 is blocked or cut off by virtue of the insert 464 provided in thepassage 462 of the backflush valve 406.

When it is desired to perform an analysis, immediately prior thereto thesample cut-off valve 400, under the control of the microprocessor 414,is activated into its activated position which serves to cut off theflow of gaseous chlorine sample to the sampling valve 402. This permitsthe gaseous chlorine sample in the sample loop 404 to depressurize.After a short period of time sufficient to accomplish thedepressurization, the sampling valve 402 is actuated into its activatedposition to start the analysis. The position of the valves 400, 402 and406 at this stage of the analysis is shown in FIG. 10.

With the valves 400, 402 and 406 positioned as shown in FIG. 10, thefirst carrier gas stream in line 453 enters the port 440 of the samplingvalve 402, passes through the passage 430, exits the port 438 and passesthrough the sampling loop 404, carrying with it the chlorine sample inthe sample loop 404. The carrier gas transports the sample from the loop404 back into the valve 402 through the port 444, and then throughpassage 432, and out of the valve 402 through the port 446 into the line452 to the backflush valve 406.

The first carrier gas stream continues to carry the sample into port 468of the backflush valve 406, through the passage 458 and out of the valve406 through the port 470 into the chromatographic column 410. The column410 serves to separate the components of the sample into methylenechloride, chloroform, and carbon tetrachloride, chlorine and otherchlorinated hydrocarbons. The chlorine elutes first from thechromatographic column 410 and is carried by the first carrier gasstream from the column 410 into the backflush valve 406 through the port476, where it passes through the passage 460 and exits the valve 6through the port 474 into the line 494 to the diverter valve 408.

Immediately prior to the elution of the chlorine from thechromatographic column 410, the diverter valve 408 is actuated into itactivated position. The chlorine being carried by the first carrier gasstream in the line 494 flows into the diverter valve 408 and is divertedout thorough the outlet 504 into the line 508 and passes to the causticscrubber 510. Thus, the chlorine is never permitted to enter thedetector 412.

The methylene chloride, chloroform and carbon tetrachloride areseparated by the chromatographic column 410 in that order. Thesecomponents follow the chlorine out of the column 410, through the port476 into the backflush valve 406, through the passage 460 and out of thevalve 406 through the port 474 into the line 494. As soon as all thechlorine has been diverted by the diverter valve 408 to the scrubber510, the diverter valve 408 is deactivated into its deactive position.The carrier gas then carries the methylene chloride, chloroform andcarbon tetrachloride from line 494 into the inlet 496 of the divertervalve 408 and out of the valve 408 through the outlet 502 into the line506 where they flow to the detector 412 for detection and measurement bythe detector 412 in that order.

After the elution of the methylene chloride, chloroform and carbontetrachloride from the chromatographic column 410 and passage into line494, the backflush valve 406 is actuated into its activated position.The positions of the valves 400, 402 and 406 after the backflush valve406 is activated is shown in FIG. 11.

As shown in FIG. 11, by this stage of the analysis, the sample cut-offvalve 400 and the sampling valve 402 may be returned to their inactivepositions. The diverter valve 408 remains in its deactive position andthe backflush valve 406 has been actuated into its activated position.With the valves in the positions shown, the first carrier gas stream,after passing through valve 402 into line 452, is blocked from flowingat port 468 of the backflush valve 406 by the slider plate 454. Thesecond carrier gas stream now flows through the line 492 and enters theport 478 of the backflush valve 406. The second carrier gas stream thenpasses through passage 460 in the valve 406, out through port 476 andinto the end 484 of the chromatographic loop 480. The second carrier gasstream flows backward through the chromatographic column 410 to the port470 of the backflush valve 406. The backward flow continues throughpassage 458 of the valve 406, out through the port 472 into the line 498to line 494. The flow of the second carrier gas stream continues in theline 494 to the diverter valve 408, which is inactive, and through thevalve 408 into line 506 to the detector 412. With this reverse flushingaction through the chromatographic column 410 by the second carrier gasstream, any other chlorinated hydrocarbons which might have been presentin the original chlorine sample and which never exited thechromatographic column 410, will exit the column 410, regroup and bedetected by the detector as a group. After a sufficient time has elapsedto detect and measure any hydrocarbons in the reverse flow, thebackflush valve 406 is deactivated and the system is ready for the nextanalysis cycle.

While not specifically shown in the drawings, the various valves 400,402, 406 and 408, the carrier fluid source 487, the sample loop 404, thechromatographic column 410, and detector 412, as well as the associatedpiping are all maintained in a temperature controlled environment withthe appropriate temperature being maintained by suitable heating meanssuch as a forced air or electric heater. This ensures that there will beno variations in temperature after the system has been calibrated whichwould effect their accuracy of the readings from one analysis toanother.

The timing of the actuation of the individual valves 400, 402, 406 and408 between their deactive and activated positions may be determinedexperimentally upon initial calibration of the analyzer 18. Such initialcalibration may be achieved introducing a calibration sample of chlorinecontaining a known-amount of the halocarbons into the sample loop andstarting the cycle. The time at which the various halocarbons elute andare passed to the detector 412 is noted and the actuation of the variousvalves 400, 402, 406 and 408 set accordingly. By using a sample of aknown quantity of the various halocarbons, the microprocessor 414 may beadjusted based upon the signal received from the detector 412 to reflectthe actual concentration of each individual component of the samplewhich will provide the set point for the other concentrations.

By way of example, the system as shown in FIGS. 9-11 may be operatedusing a 4 foot length of 1/4" tubing of 40% Kel-F® oil on acid washedChromosorb® W for the chromatographic column 410. The chromatographiccolumn 410 may be maintained at a temperature of 60° C. The carrier gasmay be high purity helium having a flow rate of 55 ml/min. The detector412 may be a flame ionization detector of the type described above withhydrogen flow thereto of 45 ml/min and air flow thereto of 250 ml/min.

With the arrangement as described immediately above, the analyticalcycle is about 780 seconds. Assuming that the cycle starts when thesampling valve 402 is actuated into its activated position, the samplecut-off valve 400 is first actuated into its activated position at about30 seconds before the actual start of the cycle. This permits time forthe sample in the sample loop 404 to depressurize. After approximately30 seconds, at a time equal to zero, the sampling valve 402 is actuatedinto its activated position to start the cycle. After about 10 secondsinto the cycle, giving time for the carrier gas stream to remove thesample from the sample loop 404, the sampling valve 402 is moved backinto its deactive position followed by the actuation of the samplecut-off valve 400 into its deactive position at about 15 seconds intothe cycle. The exact time point for actuating the sample cut-off valve400 and the sampling valve 402 back into their deactive positions is notcritical so long as they are deactivated a sufficient period of timebefore the next cycle to permit a new sample to flow into the sampleloop 404. The sampling valve 402 should preferably be moved to itsinactive position slightly prior to the actuation of the sample cut-offvalve 400 into its deactive position so that the sample from the cut-offvalve 400 will have a path through the sampling valve 402.

The elution of the chlorine from the chromatographic column 410 willoccur between about 20 and 100 seconds into the cycle so that thediverter valve 408 is actuated into its activated position at about 15seconds, a time prior to the chlorine reaching the diverter valve. Themethylene chloride elution will occur between about 120 and 168 secondsinto the cycle so that the diverter valve 408 is activated back into itsdeactive position at about 105 seconds to permit the methylene chlorideto flow to the detector 412. Chloroform elution will occur between about175 and 240 seconds, and carbon tetrachloride elution between about 250and 363 seconds. The backflush valve 406 is actuated into its activatedposition at about 365 seconds into the cycle. The heavier halocarbonswill elute between about 420 and 600 seconds. The backflush valve 406 isactuated back into its deactive position at 760 seconds ready to startthe next cycle.

The bromine in chlorine analyzer 14, non-condensable gases in chlorineanalyzer 16 and the halocarbons in chlorine analyzer 18 as describedabove in connection with FIGS. 2-3, FIGS. 4-8 and FIG. 9-11,respectively, are adapted to receive the chlorine sample in gaseousform. As described above, if the sample is taken from the process streamat a point at which the chlorine is in liquid form, it is passed throughthe vaporizer 12 to convert it to a gaseous form before it passes to arespective analyzer.

It is possible, if desired, to modify slightly the respective analyzers14, 16 and 18 so that the vaporizer 12 may be eliminated and thechlorine sample pass to the respective analyzer in its liquid formdirect from the process stream.

An example of a modified form of a bromine in chlorine analyzer 14awhich receives the chlorine in liquid form is shown in FIG. 2a. In thisembodiment, the line 46, which in the modification of FIG. 2 isconnected to the line 44 from the vaporizer 12, is instead connected tothe line 30 coming directly from the process stream. Thus, the chlorinesample in the modification of FIG. 2a enters the analyzer through line46 in liquid form.

The excess liquid chlorine exits the analyzer 14a through the samplereturn line 54 and is returned to the process stream. A portion of thechlorine from the line 52 is fed to the reaction zone 66 through theconduit 86. In this case, the conduit 86 is provided with an adjustableorifice 600 upstream of the valve 88. The orifice 600 serves to meterthe liquid chlorine sample into the reaction zone with the chlorinesample in the line 46 upstream of the orifice 600 being maintained at aconstant pressure against the orifice. A suitable metering pump may beused in place of the orifice.

With the embodiment of FIG. 2a, once the liquid chlorine is metered intothe hydrazine in the reaction zone 66, the reaction and analytical cycleand the analyzer itself are the same as explained in connection with theembodiment of FIGS. 2 and 3. Accordingly, the same references numbersare used for the same elements.

FIG. 4a shows a modified non-condensable gas in chlorine analyzer 16awhich may receive the chlorine sample in liquid form. In the case ofthis embodiment, the sample gathering and injection means of theembodiment of FIGS. 4-8, including the sample cut-off valve 202, thesampling valve 214, and the sample loop 238, is replaced by a sampleinjecting valve 620.

Referring to FIG. 4a, the sample injecting valve 620 may be a standard,commercially available, pneumatically actuated, 4-port sliding platevalve. The valve 620 is pneumatically actuatable between a deactiveposition and an activated, sample injecting position. A solenoid valve(not shown), controlled by the microprocessor 203, may control thesupply of the pneumatic fluid such as instrument air to the valve 620 tocause the movement of the valve 620 between its two positions.

The sample injecting valve 620 may include a slider plate 622 movable ina body 624 between the two positions of the valve. The slider plate 622may include three axially spaced through-bore or passages 626, 628 and630, each of which extends between the top and bottom surfaces of theslider plate 622.

The body 624 of the sample injecting valve 620 may include four ports632, 634, 636 and 638, with the ports 632 and 634 being positioned inthe top surface of the body 624 and the ports 636 and 638 beingpositioned in the bottom surface of the body 624 when the valve isorientated as shown in FIG. 4a.

When the sample injecting valve 620 is in its deactive or loadingposition, the slider plate 622 is positioned as shown in FIG. 4a. Inthis deactive or loading position, the passage 628 connects the ports632 and 636, while passage 630 connects the ports 634 and 638. Passage626 is inactive.

When the valve 620 is actuated into its activated, or injectingposition, the slider plate 624 is moved to the right as viewed in FIG.4a. In this activated, or injecting position, the passage 626 connectsthe ports 632 and 636 and passageway 628 connects the ports 634 and 638.The passage 630 is inactive.

In the case of the modification of FIG. 4a, the line 48, which in themodification of FIGS. 4-8 is connected to the line 44 from the vaporizer12, is instead connected to the line 30 coming directly from the processstream. Thus, the chlorine sample in the modification of FIG. 4a entersthe analyzer through line 48 in liquid form. The line 48 is connected tothe port 636 of the sample injecting valve 620. The sample return line54 with the flow meter 58 therein is connected to the port 632 of thevalve 620.

In the embodiment of FIG. 4a, the sample return line 54, at a pointadjacent the valve 620, is provided with a needle valve 640 or othertype of pressure control valve to maintain the pressure of the incomingliquid chlorine sample in the line 48 and as it passes through the valve620 into the return line 54 to ensure that the chlorine sample passingthrough the valve 620 remains in liquid form.

The sample outlet line 244 containing the first chromatographic column248 is connected to the port 638 and the carrier stream line 246 isconnected to the port 634. The remainder of the analyzer 16a is asdescribed in connection with the embodiment of FIGS. 4-8, with similarelements having like reference numerals.

In the deactive position of the analyzer 16a, the liquid chlorine samplefrom the process stream enters the analyzer through line 48 and entersthe sample injecting valve 620 through the port 636, passes throughpassage 628, and exits the valve 620 through the port 632 into thereturn line 54. The first carrier gas stream flows through line 246 tothe sample injecting valve 620, enters the port 634, passes throughpassage 630, and exits the valve 620 through the port 638 into line 244and proceeds in a manner similar to its path in the FIGS. 4-8embodiment.

When it is desired to take an analysis, the sample injecting valve 620is caused to be moved into its activated position under the control ofthe microprocessor 203. In the activated position of the valve 620, thepassage 628, containing a fixed volume slug of liquid chlorine sample,is moved into alignment with the ports 634 and 638 of the valve 620. Inthis position, the carrier fluid flowing into the valve 620 from line246 through the port 634, carries the chlorine sample slug out of thesample injecting valve 620 through port 638 into line 244 to thechromatographic column 248. The carrier gas, being maintained at anelevated temperature, along with the reduction in pressure, causes thechlorine sample to vaporize into its gaseous form as its exits the valve620. The analysis cycle then proceeds as described in connection withthe embodiment of FIGS. 4-8.

In FIG. 9a there is shown a modified halocarbon in chlorine analyzer 18awhich may receive the chlorine sample in liquid form. In the case ofthis embodiment, the sample gathering and injection means of theembodiment of FIGS. 9-11, including the sample cut-off valve 400, thesampling valve 402, and the sample loop 404, is replaced by a sampleinjecting valve 650.

Referring to FIG. 9a the sample injecting valve 650 is similar to thevalve 620 shown and described in connection with FIG. 4a and may be astandard, commercially available, pneumatically actuated, 4-port slidingplate valve. The valve 650 is pneumatically actuatable between adeactive position and an activated, sample injecting position. Asolenoid valve (not shown), controlled by the microprocessor 414, maycontrol the supply of the pneumatic fluid such as instrument air to thevalve 650 to cause the movement of the valve between its two positions.

The sample injecting valve 650 may include a slider plate 652 movable ina body 654 between the two positions of the valve. The slider plate 652may include three axially spaced through-bore or passages 656, 658 and660, each of which extends between the top and bottom surfaces of theslider plate 652.

The body 654 of the sample injecting valve 650 may include four ports662, 664, 666 and 668, with the ports 662 and 664 being positioned inthe top surface of the body 654 and the ports 666 and 668 beingpositioned in the bottom surface of the body 654 when the valve 650 isorientated as shown in FIG. 9a.

When the sample injecting valve 650 is in its deactive or loadingposition, the slider plate 652 is positioned as shown in FIG. 9a. Inthis deactive or loading position, the passage 658 connects the ports662 and 666, while passage 660 connects the ports 664 and 668. Passage656 is inactive.

When the sample injecting valve 650 is actuated into its activated, orinjecting position, the slider plate 652 is moved to the right as viewedin FIG. 9a. In this activated, or injecting position, the passage 656connects the ports 662 and 666 and the passageway 658 connects the ports664 and 668. The passage 660 is inactive.

In the case of the modification of FIG. 9a, the line 50, which in themodification of FIGS. 9-11 is connected to the line 44 coming from thevaporizer 12, is instead connected to the line 30 coming directly fromthe process stream. Thus, the chlorine sample in the modification ofFIG. 9a enters the analyzer through line 50 in liquid form. The line 50is connected to port 666 of the sample injecting valve 650. The samplereturn line 54 with the flow meter 58 therein is connected to port 662of the valve 650.

In the embodiment of FIG. 9a, the sample return line 54, at a pointadjacent the valve 650, is provided with a needle valve 670 or othertype of pressure control valve to maintain the pressure of the incomingliquid chlorine sample in the line 50 and as it passes through the valve650 into the return line 54 to ensure that the sample passing throughthe valve remains in liquid form. The carrier-sample outlet line 452 isconnected to the port 668 and the first carrier gas stream line 453 isconnected to port 664. The remainder of the analyzer 18a is as describedand shown in connection with the embodiment of FIGS. 9-11, with similarelements having like reference numerals.

In the deactive position of the analyzer 18a, the liquid chlorine samplefrom the process stream enters the analyzer through line 50 and entersthe sample injecting valve 650 through the port 666, passes through thepassage 658, and exits the valve 650 through the port 662 into thereturn line 54. The first carrier gas stream flows through line 453 tothe sample injecting valve 650, enters the port 664, passes through thepassage 660, and exits the valve 650 through the port 668 into the line452 and proceeds in a manner similar to its path in the FIGS. 9-11embodiment.

When it its desired to take an analysis, the sample injecting valve 650is caused to be moved into its activated position under the control ofthe microprocessor 414. In the activated position of the valve 650, thepassage 658, containing a fixed volume slug of liquid chlorine sample,is moved into alignment with the ports 664 and 668 of the valve 650. Inthis position of the valve 650, the carrier fluid flowing into the valve650 from line 453 through port 664, carries the chlorine sample slug outof the passage 660 and through the port 668 of the sample injectingvalve 650 into the line 452 to the backflush valve 406. The carrier gas,being maintained at an elevated temperature, along with the reduction inpressure, causes the chlorine sample to vaporize into its gaseous formas its exits the valve 650. The analysis cycle then proceeds asdescribed in connection with the embodiment of FIGS. 9-11.

In the case of all the embodiments discussed above, all components,including the valves and piping, of each of the various analyzers, andthe overall system, that are exposed to the virgin chlorine sample, orto a sample slug of chlorine being carried by the carrier gas which hasa relatively high concentration of chlorine, should be fabricated fromsuitable chlorine resistant material. Such materials may includechlorine resistant plastics such as Teflon (polytetrafluoroethylene) andKel-F® plastic (a chlorofluorohydrocarbon polymer) and metals such asnickel and other chlorine resistant metals.

By way of example, in the embodiment of FIGS. 2 and 3, all thecomponents, including the lines 46, 54 and 86, valves 52 and 88, flowmeters 58 and 89 and reactor 100, leading up to the separator 68 shouldbe fabricated from chlorine resistant materials. In FIG. 2a, the orifice600 should be of chlorine resistant material.

In the case of the embodiment of FIGS. 4-8, the sample cut-off valve 202and sampling valve 214 are preferably fabricated from Kel-F® plasticwhile the lines 48, 54 and 212 and the tubular sample loop 238 arepreferably fabricated from nickel. In the case of the embodiment of FIG.4a, the sampling valve 620 is preferably fabricated from a chlorineresistant material such as Kel-F® plastic.

In the embodiment of FIGS. 9-11, the sample cut-off valve 400, thesampling valve 402, the backflush valve 406, and diverter valve 408 arepreferably fabricated from a chlorine resistant plastic such as Kel-F®plastic, while the tubing forming the sample loop 404 and thechromatographic column 410 and the piping carrying the sample slug fromthe chromatographic column to the diverter valve as well as the pipingexposed to the incoming chlorine sample from the process stream arepreferably fabricated from nickel or Teflon. Such piping includes thelines 50, 54, 424, 452, 494 and 508. Any valve or flow meter within suchlines should also be fabricated from chlorine resistant material. Thesample injecting valves 620 and 650 of the embodiments of FIGS. 4a and9a respectively, are also preferably fabricated from a chlorineresistant material such as Kel-F® plastic.

By virtue of the above described system and analyzers, there is providedan effective means for determining the product quality of chlorine. Thesystem provides for the on-line detection and measurement of thesignificant contaminants which may be present in the chlorine includingbromine, non-condensable gases and halocarbons. The various analyzersare capable of continuously detecting and measuring low concentrationsof their respective contaminants with precision and accuracy, and thesystem provides a means for continuously providing information and dataregarding the quality of the chlorine on a real time basis.

While the invention has been described above with reference to specificembodiments thereof, it is apparent that many changes, modifications andvariations can be made without departing from the concept disclosedherein. Accordingly, it is intended to embrace all such changes,modifications and variations that fall within the spirit and broad scopeof the appended claims.

What is claimed is:
 1. A method for measuring the purity chlorinecomprising:a. taking a sample stream of chlorine from a chlorine source,b. passing a discrete first, second and third portion of the samplestream to a first bromine analyzer, a second non-condensable gasanalyzer and a third halocarbon detector respectively wherein, each ofthe first second and third detectors perform the designated detection inthe chlorine environment and each detector generating a first, secondand third signal in response to the respective sample streams, c.collecting the first, second and third signals in a data acquisitionnetwork for integrating and correlating the signal to measure the purityof the chlorine.
 2. The method of claim 1 wherein the sample stream istaken from a stream of liquid chlorine and further comprising the stepof converting the sample stream of liquid chlorine to a gaseous formbefore the portions of the stream are passed to the analyzers.
 3. Anapparatus for measuring the purity chlorine comprising:a. means fortaking a sample stream of chlorine from a chlorine source, b. means forpassing a discrete first, second and third portion of the sample streamto a first bromine analyzer, a second non-condensable gas analyzer and athird halocarbon detector respectively wherein, each of the first,second and third detectors perform the designated detection in achlorine environment and each detector generating a first, second andthird signal in response to the respective sample streams, c. means forcollecting the first, second and third signals in a data acquisitionnetwork means that integrates and correlates each of the signals togenerate a measure of the purity of the chlorine.
 4. The apparatus ofclaim 3 wherein the sample stream of chlorine is taken from a stream ofliquid chlorine and further comprising a vaporizer for converting theliquid chlorine sample stream to a gaseous chlorine stream before theportions of the sample stream are passed to their respective analyzers.